1. Field of the Invention
The present invention relates to a flat display device, and more particularly to a flat display device with a plurality of micro light valves which are corresponding to respective pixels for display, in which each of the micro light valves is controlled by use of electrostatic force to pass or shut a light beam, thereby displaying stationary and moving images, and a method for manufacturing the same.
2. Description of the Prior Art
In various types of light valves for passing or shutting a light beam, there is a liquid crystal display (referred to as "LCD", hereinafter) device using a liquid crystal, as typical light valve. Since such an LCD device is low in power consumption required for passing or shutting of a light beam through liquid crystal therein and is capable of driving a plurality of image pixels independently, the LCD device has been widely used in the display field.
The LCD device, as is widely used as a flat display device, can be operated by low voltage and fabricated with thin film, as compared with a conventional CRT (cathode ray tube) display. Particularly, a thin film transistor LCD device is one of the widely-used flat display devices, because it is capable of embodying a high image quality with respect to various colors.
However, when an LCD device is fabricated by up-to-date techniques, several problems which occur are as follows:
1. It is difficult to design pixel arrangement for display or to manufacture pixels in proportion to increase of the pixels.
2. As is the case with TFT (Thin Film Transistor) liquid crystal display device having a large panel, it is difficult to manufacture such a display device having a large panel. As a result, the larger the display panel is, the lower the yield of the display device.
3. Since the conventional display device, such as an LCD device, uses liquid crystal material as an intermediation for shutting and passing a light beam, it is difficult to utilize several complicated-processes, such as injection of liquid crystal materials, adjustment of space between two opposite substrates having a liquid crystal layer therebetween, forming process of orientation films for arrangement of liquid crystal, or the like. Also, for this reason, the cost of the display is very expensive.
4. The viewing angle of the LCD is lower than that of CRT.
5. Since a polarization plate has to be provided in an LCD, the large amount of light is lost.
On the other hand, in the case of mechanical light valves which have been developed recently, there is more power consumption, and it is difficult to manufacture a micro light valve or to make its operation fast. However, with the progress of semiconductor fabrication techniques, micro actuators capable of operating mechanically can be manufactured. Accordingly, if the size of such a mechanical light valve can be manufactured extremely small by semiconductor fabrication techniques, the mechanical light valve permits to pass and to shut a light beam fast by using a quite few energy.
One pixel of the LCD device is approximately 100 .mu.m.times.100 .mu.m in size, but in the case that each pixel has less than the size, the further small pixel may be sensitively operated by electrostatic force caused by low voltage, as compared to gravity acting upon a body in motion. Therefore, if problems due to a frictional force between two faced bodies in motion can be overcome, each pixel having size of less than 100 .mu.m.times.100 .mu.m can be sensitively operated fast by high electrostatic force. This operation has been experimented several times in an electrostatic motor having micron meters of several .tens in size.